• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.619-625
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• 2006

Amount of soil loss is important information for the proper water quality management, In this research, annual average soil loss of the Geum River basin was estimated using RUSLE (Revised Universal Soil Loss Equation) and GIS (Geographic Information System). Input data were manipulated using ArcGIS ver. 8.3. From crop field which constitute 8.2% of the Geum River Basin, annual average soil loss was estimated as 53.6 ton/ha/year. From the rice paddy field which constitutes 20% of the Geum River Basin, soil loss was estimated as 33.5 ton/ha/year, In comparison, forestry area which constitutes 61.8% of the basin discharged 2.8 ton/ha/year, It could be known from this research that appropriate measures should be implemented to prevent excessive soil loss from the agricultural areas.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.183-192
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• 1995

The purpose of this study was to evaluate the effect of smear layer management on the interfacial morphology between dentin bonding system and dentin. Clearfil New Bond, Scotchbond Multipurpose, Prisma Universal Bond 3 and X-R Bond were used on the cervical dentinal surfaces of bovine incisor teeth. All of the dentin bonding systems were labeled with fluorescene in primer and rhodamine B in adhesive. Specimens of 2~3mm thichness were prepared by longitudinal and labiolingual sectioning. The interface between dentin bonding system and dentin was observed by flouresence imaging with a confocal laser scanning microscope. Following results were obtained. 1. In the specimen of Clearfil New Bond, dentinal tubules were widened by destruction of peritubular dentin in the course of treatment with phosphoric acid of high concentration. 2. Hybrid layer was observed in the specimen of Scotchbond Multipurpose and X-R Bond. 3. In the specimen of Prisma Universal Bond 3, the penetraton of adhesive was not observed clearly.

• Journal of KSNVE
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• v.2 no.2
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• pp.125-134
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• 1992

In this study, ti identify the dynamic characteristics of automobile steering system which consists of many components and joints, each component combined structure was analyzed using commercial structural package, ANSYS. And, the finite element method for each component and modeling method of several joints universal joint, bolt joint, bearing, etc. were studied. On the other hand, the experimental modal analysis was performed to compare with the results of the finite element analysis and joint modeling. The result shows very close agreement between two analysis. Also, it was found that the steeing column used in this experiment does not effect the low frequency mode of entire system. In addition, we found that constraint equations need to be considered in modeling universal joint. Since the stiffness effect of Urethane around wheel could be ignored, it can be modeled only with mass effect. In the end, it was found that dynamic characteristics of the entire steerintg system depends mainly upon the wheel characteristics.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.69.2-69.2
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• 2019

Recent high resolution IR observations reveal that molecular clouds are filamentary and such a structure is ubiquitous over various star-forming environments, and it is clear that filaments play a crucial role in the formation of cores and stars. However, the formation process of dense cores in the filaments are still unknown. To investigate this issue in detail, we have carried out TRAO FUNS (TRAO survey of nearby Filamentary molecular clouds, the Universal Nursery of Stars) toward various star forming filamentary molecular clouds. In this presentation, we will report the first look results of filaments and dense cores in MCLD 123.5+24.9 and IC 5146, which are known as a quiescent, non-star-forming region and an active, high-mass star forming region, respectively. By comparing the kinematic properties of filaments and dense cores in different star forming environments, we verified the formation scenario of filaments and dense core, i.e., gravoturbulent fragmentation via supersonic motions.

• International Journal of Contents
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• v.17 no.2
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• pp.9-19
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• 2021

The purpose of this survey-based study was to investigate high school students' perceptions of mathematics teachers' implementation of Universal Design for Learning (UDL)-based practices and technology in their mathematics classes in 2017. A total of 303 high school students in South Korea participated in this online survey on teachers' use of technology for instructional practices, the frequency of technology tool use, and the meeting of UDL guidelines in mathematics instruction. According to frequency analysis, high school students generally perceived their teachers' mathematics teaching as somewhat positive in providing multiple means of representation, action and expression, and engagement. However, mathematics teachers' implementation of technology tools in their mathematics classes was generally limited. This study indicated significant and positive relationships between variables regarding the use of technology tools and teachers' efforts to follow the UDL guidelines. Applying the Chi-squared test, we further examined how each survey result differed according to high school students' academic achievements and grade levels.

• Journal of architectural history
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• v.32 no.2
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• pp.21-35
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• 2023

The purpose of this study is to develop a method for establishing an educational system for World Heritage interpretation applicable to World Heritage sites and to design an education program for World Heritage interpretation by applying the developed education system in this study. This study first identified the definition of interpretation and the relationship between interpretation and education through previous research and analyzed the role and significance of heritage interpretation due to the paradigm transition in the capacity building of World Heritage sites. Next, the educational status of World Heritage interpretation was analyzed through educational institutions, educational subjects, and curriculum examples. Finally, this study argues that a method for establishing a World Heritage interpretation education system should be presented according to the composition of the curriculum, and the interpretation curriculum planning by interpreters should be proposed focusing on the Outstanding Universal Value (OUV) of World Heritage sites.

• Journal of Life Science
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• v.22 no.6
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• pp.703-712
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• 2012

Adeno-associated virus (AAV) has been considered to be a very safe and efficient gene delivery system. However, the major obstacles to therapeutic usage of AAV have been to achieve highly efficient and reproducible production processes, and also to develop a reliable quantifying method of various serotypes with a simple protocol. We compared the efficiency of the conventional production protocol of AAV2 and adenovirus (Ad) co-infection to that of a new method containing AAV2 infection followed by pHelper transfection. We tested HEK293 and 293T, and further examined the time-dependent changes of AAV2 production. The new method of AAV2 and pHelper DNA gave about ten times higher production efficiency than that of the conventional protocol. The highest production efficiency in 293T was achieved as $1.61{\times}10^5$ virus genomes (v.g.)/cell by the new method of 10 MOI of AAV2 infection and 5 days post-infection. This protocol of the highest efficiency was then applied to produce various AAV serotypes and showed the efficiencies higher than $10^5$ v.g./cell. Next, we designed the universal PCR primers of highly conserved regions for various AAV serotypes to develop a simple and reliable titration method. The universal primers could amplify all the tested AAV serotypes with similar sensitivities by ten molecular copies. Therefore, this pair of universal primers can be further utilized to detect AAV contaminants in therapeutic adenoviral vectors.

• Restorative Dentistry and Endodontics
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• v.47 no.4
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• pp.43.1-43.13
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• 2022

Objectives: This study compared the surface gloss (SG), gloss retention (GR), and color stability (CS) of 2 universal resin composites after chemical (CA) and mechanical (MA) aging. Materials and Methods: Twenty disc-shaped samples of G-ænial A'Chord (GC-Europe) and Filtek Universal (3M-ESPE) were polished with sequential abrasive papers. For CA, specimens were stored in 1 mL of 75% ethanol for 15 days at 37℃, and readings (SG, GR, and CS) were obtained at baseline and 5, 10, and 15 days. For MA, specimens were subjected to 10,750 simulated brushing cycles. SG and CS were evaluated after every 3,583 cycles. SG was measured with a glossmeter (geometrical configuration: 60°), and values were expressed in gloss units. Color was measured with a spectrophotometer using the CIE-L^*a^*b^* color system. The Student's t-test, 1-way analysis of variance, and Scheffé test were used for statistical analysis (α = 0.05). Results: G-ænial presented significantly higher SG values than Filtek (p = 0.02), with GR reductions of 5.2% (CA) and 5.3% (MA) for G-ænial and 7.6% (CA) and 7.2% (MA) for Filtek. The aging protocol had no statistically significant effect on SG or GR (p = 0.25) from baseline to the final readings. G-ænial-MA presented the lowest color difference (ΔE = 1.8), and G-ænial-CA and Filtek-CA had the largest changes (ΔE = 8.6 and ΔE = 11.8, respectively). Conclusion: G-ænial presented higher SG values and better CS. Both restorative materials demonstrated acceptable GR and CS. Aging protocols impacted these properties negatively.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.05a
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• pp.166.2-166.2
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• 2004

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.14-20
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• 2004